Electrical switches having improved contact structure

ABSTRACT

An electrical switch including an operating member pivotally mounted on a body and carrying a spigot which extends towards the base of the body, on which the fixed contacts are positioned. A movable contact member slidable on the base includes a pair of resiliently electrically interconnected parts engageable with the fixed contacts, the contact member being engaged with the spigot. A compression spring surrounds the spigot and urges the contact member into engagement with the base, the compression spring acting as part of an overcenter mechanism.

United States Patent Foley m1 Feb. 15, 1972 1 ELECTRI SWITCHES HAVING3.529.109 9/1929 can"; ....200/|oo an x IMPROVED CONTACT STRUCTURE3,427.05 2/1969' Avner ..200/76 R [72] Inventor: David Foley, Bumley,England Pr M H imary 'ner- .0. Jones [731 m M Attorney-Holman. Glascock,Downing qt Seebold [22] Filed: May 20, 1970 ABSTRACT v An electricalswitch including an operating member pivotally mounted on a body andcarrying a spigot which extends [301 F s n h Prlwlty M 1 toward: thebase ofthe body, on which the fixed contacts are .Iune I2 1969 GreatBritain ..29 753/69 A member slidabk b 1 9 includes a pair ofresiliently electrically interconnected parts I 52] Us. (1 goo 3engageable with the fixed contacts, the contact member being 5 m c no 3engaged with the spigot. A compression spring surrounds the [58]ileldnlsesrch ..200ll66Bl-I, 16 R, 76 R spigot and urges the contactmember into engagement with the base, the compression spring acting aspart of an over- [56] lleieneaees Cited center mechanism.

UNITED STATES PATENTS 2 Claims, 2 Drawing Figures 3,299,227 I] I967Schaad et al.' ..200ll6 R PATENTEDFEBIS I972 3.643.051 V INVENTOR flaw/4 ATTORNIE ELECTRICAL SWITCHES HAVING IMPROVED CONTACT STRUCTURE Thisinvention relates to electrical switches.

A switchaccording to the invention comprises, a body having a base, aplurality of fixed contacts carried by the base and insulated from oneanother, an operating member pivotally mounted on the body, a spigotcarried by the operating member, the spigot extending towards the base,a movable contact member slidable on the base and including a pair ofresilient electrically interconnected parts engageable with the fixedcontacts, said contact member being engaged with said spigot, and acompression spring surrounding said spigot and urging said contactmember into engagement with the base, the arrangement being such thatpivotal movement of the operating member relative to the body istransmitted by said spigot to the contact member to cause said contactmember to slide relative to the base, said spring acting as part of anovercenter mechanism urging the movable contact member and the operatingmember to one side or the other of a central position.

One example of the invention is illustrated in the accompanyingdrawings, wherein FIG. 1 is a sectional view of an electrical switch,and

FIG. 2 is a plan view of the movable contact member of the switch shownin FIG. 1.

Referring to the drawings, the switch includes a hollow molded syntheticresin body 11 which is open at one end, and which is closed at the otherend by an integral base 12. Set in the base 12, and flush with the innersurface of the base are a plurality of fixed contacts 13 each of whichis electrically connected to a respective blade connector on theexterior of the base. Upstanding from opposite sidewalls of the body 11are a pair of lugs 14 (one of which is shown in FIG. I) and extendingbetween the lugs 14 and pivotally mounted thereon is a molded syntheticresin, rockertype operating member 15. Integral with the operatingmember 15 and extending towards the base 12 is a cylindrical spigot 16which is engaged at its free end with a movable contact member 17. Themovable contact member 17 is stamped from a strip of phosphor bronze,and is generally I-l-shaped. The limbs 18 of the H- shaped member 17 arecurved downwardly out of the plane of the remainder of the member 17,and define independently resilient arms engaging the base 12. Thecentral portion of the member 17 is formed with an elongated slot 19through which the free end of the spigot 16 extends, and the contactmember 17 is urged firmly into engagement with the inner surface of thebase 12 by a compression spring 21 which surrounds the spigot 16 andwhich acts between the operating member 15 and the contact member 17. Itwill be noted that the material of the member 17 is chosen to impartresilience to the arms.

Copper, which is commonly used for contacts, is not suitable for thispurpose.

The fixed contacts 13 are arranged in pairs, only one of each pair beingshown in the drawings. The contacts in each pair of contacts arepositioned side by side, and are spaced apart by a distance equal to thewidth of the contact member 17. Thus, when one of the contacts 13 of apair of contacts is engaged by one of the limbs 18 of the movablecontact member 17, then the other contact of that pair will be engagedby a further limb 18 of the contact member 17 and the two contacts ofthe pair will be electrically interconnected through the contact member17. The position of the contact 13 on the base 12 will be dependent uponthe intended function of the switch, and clearly, since the member 17has four limbs, then four fixed contacts can be electricallyinterconnected simultaneously. FIG. 1 shows theswitch in a positionwherein the contact member 17 is bridging the extreme right-hand pair ofcontacts 13, and by pivoting the operating member 15 in a clockwisedirection, as shown in the drawings, the member 17 can be moved to theleft, to bridge the extreme left-hand pair of contacts and the centralpair of contacts simultaneously, so

that all four contacts would be electrically connected.

hen the operating member 15 1S pivoted relative to the body 11, thespigot 16, which extends through the slot 19 in the member 17 engagesone end of the slot 19, and thereafter the member 17 is moved with thespigot 16 the member 17 sliding on the base 12, and remainingsubstantially parallel with the base 12. The spring 21 will be stressedto the greatest extent when the spigot 16 is at right angles to the base12, and

so the spring 21 serves to bias the operating member to one side or theother of the central position wherein the spigot 16 is at right anglesto the base 12. Thus, during movement of the operating member 15 to movethe contact member 17 from one end of the base to the other, initiallyresistance will be felt to the movement of the operating member, as thespigot approaches the position wherein it is at right angles to thebase, and subsequently, when the spigot 16 has moved beyond the centralposition, then the spring 21 will aid the pivoting movement of theoperating member 15.

The end walls of the body 11 of the switch are formed with respective,resilient lugs 22 by means of which the switch can be engaged as a snapfit in an aperture in a mounting plate. It will be appreciated that thespigot 16 need not be cylindrical and could, for example, be ofrectangular cross section.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. An electrical switch comprising a body having a base a plurality offixed contacts carried by the base and insulated from one another, anoperating member pivotally mounted on the body, a spigot carried by theoperating member, the spigot extending towards the base, a movablecontact member slidable on the base and defined by a conductive striphaving a hole therein through which said spigot passes, and including apair of integral resilient electrically interconnected parts engageablewith the fixed contacts, and a compression spring surrounding saidspigot and urging said contact member into engagement with the base, thearrangement being such that pivotal movement of the operating memberrelative to the body is transmitted by said spigot to the contact memberto cause said contact member to slide relative to the base, said springacting as part of an overcenter mechanism urging the contact member andthe operating member to one side or the other of a central position.

2. A switch as claimed in claim 1 in which the strip is H- shaped todefine four independently resilient contacts.

t i i I

1. An electrical switch comprising a body having a base a plurality offixed contacts carried by the base and insulated from one another, anoperating member pivotally mounted on the body, a spigot carried by theoperating member, the spigot extending towards the base, a movablecontact member slidable on the base and defined by a conductive striphaving a hole therein through which said spigot passes, and including apair of integral resilient electrically interconnected parts engageablewith the fixed contacts, and a compression spring surrounding saidspigot and urging said contact member into engagement with the base, thearrangement being such that pivotal movement of the operating memberrelative to the body is transmitted by said spigot to the contact memberto cause said contact member to slide relative to the base, said springacting as part of an overcenter mechanism urging the contact member andthe operating member to one side or the other of a central position. 2.A switch as claimed in claim 1 in which the strip is H-shaped to definefour independently resilient contacts.